    public void visitExec(JCExpressionStatement tree) {
        DEBUG.P(this,"visitExec(1)");
        DEBUG.P("tree.expr.tag="+tree.expr.myTreeTag());
		// Optimize x++ to ++x and x-- to --x.
		if (tree.expr.tag == JCTree.POSTINC) tree.expr.tag = JCTree.PREINC;
		else if (tree.expr.tag == JCTree.POSTDEC) tree.expr.tag = JCTree.PREDEC;
		genExpr(tree.expr, tree.expr.type).drop();
		DEBUG.P(0,this,"visitExec(1)");
    }